[Pre537] Add success status response code check to lib/github_advisory_sync.rb for embedded to description field URLs #935

[Pre537] Add success status response code check to lib/github_advisory_sync.rb for embedded URLs

Currently best mitigation idea is to flag non-successful status response
codes and manually replace them from https://archive.org/web data.

FIelds involved are:
C. Embedded to description: field (strength goal)